1. Field of the Invention
The present invention relates to a coating agent for forming fine pattern and a method of slimming treatment on a positive type resist pattern using the above coating agent for forming fine pattern.
2. Related Art
In the production of electronic components, such as semiconductor devices and liquid crystal devices, photolithographic techniques have been used when a process such as etching is performed on a substrate. In the photolithographic techniques, a coat film (resist layer) is formed on a substrate using a so-called photoresist material responsive to actinic radiation, then the resist layer is selectively irradiated with the actinic radiation in order to perform light exposure, and thereafter a developing treatment is performed to selectively dissolve and remove the resist layer so as to form an image pattern (resist pattern) on the substrate. Then, a wiring pattern is formed on the substrate by carrying out an etching process with this resist pattern as a protective layer (mask pattern).
In unison with a recent growing tendency to highly integrate and miniaturize semiconductor devices, fine-fabrication in the formation of these resist patterns has also advanced and thus ultra-fine-processing is required. In addition to attempt to achieve such ultra-fine-fabrication of the resist pattern, research and development of techniques have been performed in order for the pattern fine-fabrication to exceed the resolution limit of the resist materials also in view of pattern formation methods.
For example, as a method of forming an ultra-fine resist pattern, a method using a coating agent containing at least one selected from a water-soluble resin and an alkali-soluble resin is known (Patent Document 1). According to the method described in Patent Document 1, an ultra-fine resist pattern is formed by applying a coating agent on the surface of a resist pattern formed on a substrate to form a coat film, and then developing with water or a weakly alkaline aqueous solution.
In the method, the coat film is formed on the surface of a resist pattern having a resist section comprising a resist composition and a nonresist section, and then the surface of the resist section is impregnated with a resin component contained in the coat film to form a mixing layer on the surface of the resist section. Then, through removal of the mixing layer along with the coat film by development, a fine resist pattern comprising a resist section having a smaller dimension by the amount of the removed mixing layer as compared with that of the resist pattern before applying the coating agent (hereinafter, a process of fining a resist pattern by reducing a dimension of a resist section through removal and dissolution of a surface layer of the resist pattern is also referred to as slimming).
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2003-215814